1. Field of the Invention
The present invention generally relates to magnetic disk storage technology and, more particularly, to a method for monitoring the performance of the interface of a head/slider combination and a magnetic disk, especially a magnetic disk storage system, in which a triboelectric current is generated due to rubbing contact between slider and disk surface. The present invention also pertains to a device for preventing data losses due to head-slider/disk interferences in magnetic disk storage systems in which a triboelectric current is observed.
2. Prior Art
In magnetic disk storage systems the interface between the combination consisting of the magnetic transducer head and the slider and the surface of the magneti disk is of great importance. As the slider carries the head and contains air bearing surfaces and slides during normal disk operation on an extremely thin air cushion over the disk surface, the possibility of interferences between head and disk, so-called head disk interferences (HDI) where the head touches the surface of the disk, cannot be excluded. So HDIs are very detrimental both to the slider and its suspension and also to the surface of the disk. This can lead to irreversible damages to the surface of the disk and to the head-slider oombination. In both cases irreversible data losses are possible and are to be guarded against.
In accordance with the commonly assigned Patent Application entitled "System for Testing Magnetic Head/Disk Interfaces" Ser. No. 856,306, filed 4-28-86, now U.S. Pat. No. 4,724,392, it is described that there exist magnetic storage systems in which a triboelectric current can be observed between the head/slider combination on one side and the surface of the magnetic disk on the other side in case of rubbing contact between these two interface partners. The above-identified application describes a method for measuring and testing the properties of the interface of a slider carrying ammagnetic transducer head and a disk in a magnetic disk storage apparatus which is characterized by adjusting the rotational speed of the disk such that there is a rubbing contact between the slider and the disk, in that the thus generated triboelectric current between disk and slider is measured during a measuring/testing period, and in that the amplitude curve of this triboelectric current is analyzed over a time period.
This known method deals predominantly with the testing of the disk/slider interface and the lifetime testing of magnetic head sliders and/or magnetic disks respectively. This method does not deal with the question of monitoring the performance of the head/slider combination in cooperation with the disk surface in a magnetic disk storage system, especially under the aspect of avoiding data losses due to upcoming head crashes and disk surface destroying events.